Download presentation
Presentation is loading. Please wait.
Published byJasper Fowler Modified over 9 years ago
2
HIRLAM-6, development since last time Strategy - ALADIN - MF - collaboration Data assimilation, 3D/4D-VAR, surface Observation Usage Parameterisation – –turbulence and convection –Surface and radiation Physics coupling - boundary conditions Meso-scale modelling EPS Regular Cycle with the Reference (FMI)
3
HIRLAM-6 Memorandum of Understanding Targets –achieve highest possible accuracy for severe weather and of wind, precipitation and temperature –develop 3D/4D-VAR further and its use of non- conventional data –maintain the regular analysis/forecasting cycle –continue development of synoptic model 10-20 km –develop meso-scale non-hydrostatic operational model with suitable physical parameterisation –Overhaul of complete System –develop methods for probabilistic forecasting –continue development of verification methods
4
HIRLAM strategy - synoptic Synoptic model, 10-20 km, every 6 hours -> 2 (3) days, 4D-VAR and satellite data over a (fairly) large area –provides comprehensive set of forecast parameters for applications and driving other models –boundary conditions and tight coupling to meso-scale model –covers window between ECMWF forecasts - more recent observations and boundaries (frames)
5
HIRLAM strategy - meso-scale Meso-scale data assimilation and model, 2-3 km non- hydrostatic model +3-12 (24 h) –physics for 2km, explicit convection –turbulence and radiation non-local (later, ~ 1 km ) –rapid update cycle, vast amount of regional data available, conv/non-conv, reflectivity, precipitation.. –4D-VAR /3D-VAR FGAT - if in short time - spinup? –Boundary field impact, transparent boundary conditions !
6
HIRLAM strategy - meso-scale
8
HIRLAM research profile Physics interfaces - combinations –HIRLAM physics / AROME physics Synoptic physics HIRLAM/ALARO Synoptic 4D-VAR - migrate to ALARO Meso-scale 4D-VAR Meso-scale basis functions - J b - Observations - radar winds, surface, refl. Cloud, Large scale coupling - spectral - extension zone Meso-scale validation Probabilities with EPS and physical perturbations Surface modelling and assimilation (SST)
9
HIRLAM meso-scale group Learning - set up of ALADIN - climate - coupling DMI-SMHI-FMI-INM - Set up of domain(s) Physics interface - temporary - general HIRLAM and AROME First experiments Coupling with HIRLAM outer model
10
Data assimilation -3D-VAR 3D-VAR background constraint J b : –(x b - H(y)) T B -1 (x b - H(y)), sigma-b, horizontal variation, new structure functions => Background check, analysis increments Analytical balance (enh) ->statistical balance
11
3D-VAR (cont) FGAT - First Guess at Appropriate Time
12
4D-VAR Data Assimilation Adjoints of semi-Lagrangian spectral model Multi-incremental minimisation - low resolution Optimisations of transforms –> significant gain in economy, feasible for operations
13
4D-VAR single obs 3 Dec 99 06-12 3 Dec 06 ->3 Dec 12
14
4D-VAR argument Optimal solution in time including all information Iterativ method enabels non-linear operators - possible in 3D too, but : Non-linear analysis can transfer a vortex The model analyses non-observed quantaties Possible to use integrated observations Enables high time resolution of data and time sequence can be utilised - e.g. radar Model generated structure functions necessary for meso-scale
15
4D-VAR Estimated computer requirements of SL incremental 4D-VAR Estimated cost of SL incremental 4D-VAR
16
4D-VAR activity now Jc DFI - control of noise - NNMI in iterations Optimisation Multi-incremental and real trials 120 - 45 km minimisation, 22 - 17 km fcs about 1 hour for very large area
17
Analysis of surface parameters OI SST and Ice analysis –Ocean Sea Ice SAF data - New OI snow analysis ready for implementation –QC and bias correction (due to height differences) Tuning of 2m T och RH analysis (statistics) Old New
18
New Snow analysis SSM/I will help – LAND SAF data -
19
Observation Usage Conventional data –radiosonde launch times –radiosonde drift –comparing observation availability Remote sensing data –AMSU-A –AMSU-B –QuikScat –Radar doppler winds –GPS ZTD –WINDPROFILER
22
Reference caseGPS includedRadar 20020712_06 (analysis time)
24
Forecast Model - parameterisation Turbulence (CBR TKE-l) –Much attention to stable case - more mixing at high stability - modified - cut - smooth Ri >1 –Increased roughness - vegetational - orografical –Direction of surface stress vector –=> filling of lows, reduce 10 m wind –Moist conservative and moist stability version effect of condensation on stability
25
Stable stratification - increased mixing
26
Increased vegetational roughness
27
Turning of wind stress
28
Turning of wind stress II
29
Turning of stress and smooth mixing (Tijm, 2004)
30
Snow scheme in ISBA main modifications to original code: Only new snow scheme on fractions 3 and 4 and now 5 Force-restore formulation replaced by heat conduction Heat capacity of uppermost layer replaced by 1 cm moist soil. A second soil layer (7.2 cm) Forest area decreased so that at least 10% of area is low-vegetation At present (temporarily!) no soil freezing Forest tile, being developed - canopy snow and ground
31
Tclim ISBA: snow covering parts of fractions 3 and 4 Td snow Td 3 and 4 Ts2 snow Ts2 3 and 4 Ts snow Ts 3 and 4 T snow Thermally active layer snow in beginning of timestep Snow change mixing of T in soil between timesteps Features of the snow scheme: move the snow from fractions 3 and 4 to fraction 6 every timestep one layer of the snow, with a thermally active layer < 15 cm water in the snow, which can refreeze varying albedo and density mirroring of temperature profile in the ground to assure correct memory
34
Soil moisture adapts in assimilation to different vegetation types
35
Radiation and snow cover Soil Freezing - implemented e sat for ground <0 for ice implemented e sat over water and ice following K-I Ivarsson distribution water - ice in clouds to be consistent - large effect on emissivity - implemented radiation for sloping ground calculated - for HR
36
Radiation and condensation
37
Convection - condensation Kain-Fritsch Rash-Kristjanson –extensive tests and verification at 22 km better humidity –11 km indicates better results –Expensive, and very much so, on vector systems –Possible vectorised version
38
Model dynamics and embedding Coupling between SL advection and physics Semi-Lagrangian mods for orography (T eq.) Boundary relaxation (Host orography, interp.) Development of transparent boundary conditions Incremental Digital Filter Initialisisation Ensemble forecasts with HIRLAM Verification methods - meso-scale - Workshop Climate system developments System - upgrades - Reference test - RCR Communication - HeXNeT - RCR monitoring
39
Tanguy-Ritchie SL T-equation, SL extr
40
Transparent Boundary conditions
41
Transparent LBC progress 2D-shallow water model - several results 3D-simplest 2 layer baroclinic 3D-multilevel Z - –eigenvalues - Laplace transform –demonstrated 3D-mulitlevel eta - to be done Spectral LAM - extension zone - programming ?
42
New HR rotated climate data sets 0.0250.0125
44
Conclusions Systematic near surface errors adressed and worked on –turbulence, surface scheme, radiation-clouds New orientation towards Meso-scale Collaboration with ALADIN 4D-VAR for synoptic scales More remote sensing Lateral Boundary conditions developing - necessary Monitoring and quality of Reference system
45
Bias corrected
46
SMHI HIRLAM - 11 km -> HR-FAR
47
SMHI HIRLAM - Dec -> HR-FAR
48
Effect from esat condensation och radiation
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.